peptide bond with proline Isomerization barrier of peptide bonds in proline containing molecules - Cisprolinevs transproline peptide The Unique Nature of the Peptide Bond with Proline

Α helix The peptide bond is the fundamental linkage that forms the backbone of proteins and peptides. However, when proline, a unique cyclic amino acid, is involved in forming this bond, it introduces distinct characteristics that set it apart from other amino acid linkagesHydrogen Bonds in Peptides and Proteins: Studies of .... Understanding the peptide bond with proline is crucial for comprehending protein structure, function, and the intricate processes of protein synthesis.作者：D Piszkiewicz·1970·被引用次数：355—Aspartyl-proline peptide bondshave been found to be hydrolyzed during exposure to low pH valuesunder conditions where other aspartyl bonds are stable.

One of the most significant aspects of proline's involvement in peptide bonds is its impact on the rate of their formation. Research indicates that proline impedes the rate of peptide bond formation during protein synthesis, leading to ribosome stalling. Specifically, studies have found that Pro incorporates in translation significantly more slowly than other amino acids like phenylalanine or alanine. This slower incorporation is attributed to the fact that proline contains a secondary amino group rather than a primary one, which influences the kinetics of the peptide bond formation reaction. This phenomenon is sometimes referred to as a "kinetic bottleneck" in protein folding, particularly in proteins rich in proline residues.

Furthermore, the structure of proline itself, with its pyrrolidine ring attached to the alpha-amino group, confers unique conformational constraints on the peptide chain作者：MY Pavlov·2009·被引用次数：409—We find thatPro incorporates in translation significantly more slowlythan Phe or Ala and that other N-alkylamino acids incorporate much more slowly.. Unlike other amino acids, proline does not have a hydrogen on its alpha-amino group. This structural feature means it cannot donate a hydrogen bond to stabilize secondary structures like alpha-helices or beta-sheets. In fact, proline is often described as a "structure breaker" because it can introduce kinks into the peptide backbone.Statistically significant dependence of the Xaa-Pro peptide ...

The peptide bond involving proline also exhibits a notable characteristic related to its conformation: isomerism. While most peptide bonds predominantly exist in the *trans* conformation, peptide bonds to proline and other N-substituted amino acids are capable of populating both *cis* and *trans* isomers. This ability to isomerize around the peptide bond and sample a *cis* conformation is a unique attribute of proline.作者：D Pahlke·2005·被引用次数：55—Nuclear magnetic resonance (NMR) experiments have shown that the cis/trans ratio depends on the amino acid sequence adjacent to theproline. This isomerization is widely recognized as a significant factor in protein folding dynamics. The isomerization barrier of peptide bonds in proline containing molecules can be influenced by various factors, including concomitant pyrrolidine puckering changes. The *cis/trans* ratio of these proline peptide bonds can depend on the adjacent amino acid sequence.

The structural implications of proline's presence extend to its influence on nearby peptide bonds作者：G Vanhoof·1995·被引用次数：623—Many biologically importantpeptidesequences containproline. It confers unique conformational constraints on thepeptidechain.. Proline residues confer unique structural constraints on peptide chains and can markedly influence the susceptibility of proximal peptide bonds to protease activity. For instance, aspartyl-proline peptide bonds have been observed to be hydrolyzed during exposure to low pH values under conditions where other aspartyl bonds remain stable. This suggests a unique chemical lability associated with certain proline-containing linkages.作者：A Yaron·1993·被引用次数：748—Proline residues confer unique structural constraints on peptide chainsand markedly influence the susceptibility of proximal peptide bonds to protease activity ...

The study of the peptide bond with proline is an active area of research, with ongoing investigations into its chemical cleavage and biological processingPharmacokinetics, distribution, metabolism, and excretion of body .... For example, there are documented procedures for Chemical Cleavage of Proline Peptide BondsSlow peptide bond formation by proline and other N- .... Moreover, the role of proline in protein synthesis and folding is a subject of considerable interest, with researchers exploring the molecular insights into protein synthesis with proline residues.

In summary, proline, an amino acid obtained by hydrolysis of proteins, plays a special role in protein structure due to its unique peptide bond characteristics. Its slower incorporation into peptide chains, its inability to donate hydrogen bonds for secondary structure stabilization, and its propensity for *cis/trans* isomerization all contribute to its distinct influence on protein conformation and dynamics. Understanding these nuances is fundamental to unraveling the complexities of biological macromolecules.